Efficacy of the Bollgard Gene in Transgenic Cotton Lines Against Bollworm and Tobacco Budworm, 1995

Abstract

Abstract Transgenic cotton lines expressing an insecticidal protein produced by the crylA(c) gene (i.e., BoUgard Gene), or cryllA gene (Monsanto Co.) from Bacillus thuringiensis kurstaki, and the nontransgenic parent line Coker 312 (COK 312), were planted 25 Apr 1995 near Corpus Christi, Texas. Field plots were 4 row (38 inch centers) X 30 ft. Treatments (i.e., cotton lines) were arranged in a split plot RCB and each plot replicated 6 times. The main plot was lepidopteran control (i.e., with or without lepidopteran sprays of Karate (0.03 lb[AI]/acre) to suppress tobacco budworm, bollworm and other lepidopteran pests) and subplots were 6 cotton lines. Plots for lepidopteran suppression were sprayed on 6, 14, 21, 28 Jul with Karate using a backpack, CO2 powered sprayer and a 2 row handheld spray boom. The entire test was planted with in-furrow insecticide and oversprayed as needed for inseason control of insect pests such as thrips, aphids, boll weevil and cotton fleahopper. Efficacy of transgenic cottons to control target lepidopteran pests was determined by examining 20 flower buds and 20 capsules per plot on 5, 12, 19, 26 Jul for bollworm-tobacco budworm feeding injury, and taking lint yields per plot. Supplemental soil moisture was provided by sprinkler and furrow irrigation during the season but not within 48 h following a lepidopteran control spray. The plots were hand-harvested (13 ft 9 inches from middle 2 rows) and seedcotton ginned on a laboratory 10-saw gin.